There are increasing concerns about the potential effects of a proposed coal mine development in southern Alberta and the impacts selenium could have on the environment in southern Alberta and into Saskatchewan. The proposed Grassy Mountain Coal project would be an open-pit mine built on a former coal-mining area about seven km north of Blairmore in the Crowsnest Pass.
There are concerns that selenium could be blown by winds impacting lands used for cattle grazing, or seep into surface water, polluting downstream waterways. Should local ranchers be concerned about impacts on rangelands? Should water users and irrigation farmers in southern Alberta and Saskatchewan be concerned about impacts on water quality for human consumption, livestock watering and effects on irrigated lands and crops?
The project would include a coal preparation plant, a surface coal mine, and other infrastructure, located on a combination of Crown lands and private lands. The project would occupy about 7,000 acres of land within the Municipal District of Ranchland in Townships 8 and 9, and Ranges 3 and 4, west of the fifth meridian. The project would produce about 93 million tonnes of coal over a proposed 25-year mine life.
Read Also
Limiting Canadian exposure, I am not alone
Canada’s government may still be in its honeymoon with voters, but not with investors, Herman VanGenderen writes, citing reports that foreign investors are divesting Canadian assets while Canadians are boosting exposure in foreign securities.
Blairmore Creek and Gold Creek, which flow into the Crowsnest River, are near the south end of the project. Daisey Creek is near the north end of the project. Both Daisy Creek and Crowsnest River flow into the Oldman River and the Oldman dam. Downstream, the Oldman River joins the Bow River to become the South Saskatchewan River. Changes in water quality in the Oldman River could impact towns and cities downstream including Lethbridge, Medicine Hat and Saskatoon. Irrigation farmers that take water from the Oldman or South Saskatchewan Rivers could be impacted.
Where the selenium is
Selenium (Se) occurs naturally in the environment at very low levels. Selenium is present in coal at mean concentrations of three milligrams per kilogram (mg/kg) with a general range between 0.05 to 10.7 mg/kg. Both anthropogenic and natural sources of Se contribute to the presence of Se in the environment. The natural sources of Se are the weathering of rocks, minerals and soil, which contain minute amounts of Se.
In 1992, the Geological Survey of Canada noted Se levels in Alberta soils ranged from 0.1 to 2.7 mg/kg, Saskatchewan soils ranged from 0.1 to 3.1 mg/kg and Manitoba soils ranged from 0.1 to 4.7 mg/kg. Elemental Se is essentially insoluble. In soil, Se occurs in salts of selenic and selenious acids, selenates and selenites. Selenates are more mobile in soil due to their higher solubility and inability to adsorb onto soil particles.
Plant roots will take up soluble forms of Se, but Se is not required for plant growth. Selenium uptake by plants is affected by various soil characteristics including soil texture, acidity/alkalinity (pH), redox potential (Eh), organic matter, clay content, soil levels of sulphate and phosphate, and Se levels in the soil. Different plant species have varying ability to accumulate Se. Plant uptake of Se tends to be greater in higher-pH soils, but lower uptake occurs in soils with higher clay, organic matter or soils with higher sulphate levels.
Selenium taken up by plants is translocated to all parts of the plant, but concentrations are usually higher in seed than leaves or stems. Plant accumulation of Se is usually less than one mg/kg.
Selenium is a required nutrient for livestock and humans. Livestock depend on Se in forages to meet their Se requirements. Selenium requirements for domestic animals are in the range of 0.1 to 0.3 mg/kg in dry matter but can become toxic if present in slightly greater amounts.
(For detailed information on Se in soil, consult the soil quality guidelines in the Canadian Council of Ministers of the Environment (2009) report.)
Health Canada reports the maximum acceptable concentration for total Se in drinking water is 50 micrograms/litre (µg /L). This is also the standard used in the province of Alberta. However, the B.C. Ministry of the Environment (2014) has set maximum acceptable concentration for Se in drinking water at 10 µg/L, for irrigation water at 10 µg/L and for livestock watering at 30 µg/L.
For the average person, these scientific units may be hard to comprehend. If we use the Se level of 50 µg/L of water, that is about 50 parts per billion. To put this in terms of time, it would be about the same as 50 seconds in 31.7 years. This is an extremely small amount of Se — but also a very significant and critical amount.
Conversions for context
- 1 milligram/kilogram (mg/kg) = 1 part per million (p.p.m.)
- 1 microgram/litre (µg /L) = 1 part per billion (p.p.b.)
- 1 milligram/litre (mg/L) = 1,000 micrograms/litre (µg /L)
Selenium in surface water?
Selenium can enter surface water naturally due to erosion and weathering of soil and rock materials and move in runoff from precipitation and snowmelt into surface waters. In southern Alberta, Se in surface water is normally extremely low and well below acceptable concentrations — except downstream from former coal mining sites.
Open pit coal mining increases erosion and weathering of disturbed rock formations and soils, potentially causing enhanced Se concentrations in surface water runoff into nearby streams and lakes.
The original Grassy Mountain coal mine was abandoned about 60 years ago and was never reclaimed. A report by Colin Cooke, Craig Emmerton and Paul Drevnick (2024) reviewed information and water quality data from the Grassy Mountain site and the region. The Alberta researchers found coal mining left a legacy of disturbed landscapes and abandoned infrastructure with clear impacts on water resources.
The authors noted the intensity and persistence of water pollution. Pollution and contamination have been poorly characterized in the area. The researchers collected water samples downstream of two historical coal mines, Tent Mountain and Grassy Mountain.
Tent Mountain is a partially reclaimed surface mine that closed in 1983. Selenium concentrations downstream of Tent Mountain reached 185 μg/L in a lake below the mine spoil pile, and up to 23 μg/L in Crowsnest Creek, which drains the lake and the mine property. The authors noted that in 2019, two streams draining the waste rock pile at Tent Mountain were sampled and analyzed for dissolved Se and concentrations ranged from 119 to 801 μg/L — well above maximum acceptable concentrations.
Lessons from B.C.
West of the proposed Grassy Mountain project in southeastern British Columbia’s Elk Valley are a number of open-pit mines. Selenium in the Elk River has become a very serious issue. The city of Fernie cannot take its drinking water from the Elk River due to excessive Se levels in the river. Fernie must take its drinking water from Fairy Creek and two wells.
Cooke et al, in their report, noted waste rock, generated during coal mining in the Elk Valley, is stockpiled in nearby valleys where precipitation-induced leaching of Se has raised Se concentrations and loads in the Elk River. The Elk River then transports this Se and other contaminants downstream to Lake Koocanusa, a reservoir that crosses the Canada-U.S. border in B.C. and Montana, resulting in international water quality concerns. Cooke and co-researchers expect a legacy of coal mining inputs rests in the bed sediment of Lake Koocanusa, including Se and other compounds. They expect the input of these contaminants to continue long after the Elk Valley coal mines close.
Wyatt Petryshen of conservation organization Wildsight in 2023 conducted a study looking at fugitive coal dust in the Elk Valley and noted a strong relationship between proximity to mountaintop coal mines and increased Se contamination, as well as other potentially toxic elements including silver, germanium, nickel, uranium, vanadium and zirconium. This study found contamination was highest immediately surrounding mountaintop mines and decreased at increasing distances from fugitive dust sources. Based on the conclusions of this study, the author recommended other mining jurisdictions in mountainous regions should be aware of the risk fugitive coal dust emissions pose to community health and the environment.
Cooke and Drevnick, in a separate paper in 2022, noted long-range atmospheric transport and deposition of contaminants including Se occurring from southeastern B.C. into southwestern Alberta. Fugitive coal dust emitted from the nearby Elk Valley coal mines in B.C. may be playing a role, as these mines were shown recently to be an important regional source of atmospheric emissions downwind in southern Alberta.
Managing selenium in water
It only takes minute amounts of Se in water to exceed safe levels for human consumption or for irrigated crop production. To remove Se from water is very costly and very difficult. In Canada, the greatest Se contamination problem in surface waters is in the Elk Valley of B.C. The owner of the mines has been making great efforts to improve the Se pollution problem, but only with limited success; Se continues to be a significant problem. Some researchers (Cooke et al., 2024) suggest the problem will likely continue for many years.
A research team from China’s Nanjing University (Li et al., 2022) conducted a critical review of more than 100 research papers published in the past decade of applications, characteristics and latest developments of various technologies for the treatment of Se-polluted water. They concluded that although there are promising methods in treating Se in water, further studies are still needed to develop sustainable strategies based on existing and new technologies.
Downstream concerns
Should downstream water users in southern Alberta and into Saskatchewan be very concerned if the Grassy Mountain Coal Project goes ahead? In my opinion, yes: water users should be very concerned.
If your drinking water comes from the Crowsnest River, Oldman River or South Saskatchewan River, you should be concerned. If water is used from these rivers for livestock watering, you should be concerned. Rangelands downwind of the project could be affected by fugitive coal dust.
For irrigation farmers, whether in southern Alberta or in Saskatchewan: if your irrigation water is sourced downstream from this project, I would be concerned. What will the Se levels be in irrigation water if the project goes ahead? How will Se in irrigation water affect Se levels in soil? What will be the effects of elevated Se levels in plants and harvested crops? These are all questions that will need to be addressed.
We need to be very aware and learn from our neighbours of the long-term Se pollution problems in southeastern B.C. and into the United States. In my opinion, the potential pollution and contamination risks in the long term to our drinking water and irrigated lands in Alberta and Saskatchewan are simply too high.
